This section provides background information related to the present disclosure which is not necessarily prior art.
Sophisticated units for cooling/heating of enclosed spaces such as residential and commercial buildings have been developed for providing greater comfort to occupants of such spaces. Typically, in any unit, control systems are coupled with the unit for controlling the operation of the unit. Control systems generate signals which turn the unit ON/OFF, thereby providing a comfortable temperature regulated environment. Typically, control systems generate these signals in response to signals from feedback systems.
For large residences or commercial installations, where capacity requirements for cooling/heating of an enclosed space are high, instead of using a single large unit, it is preferable to use two or more units together in order to provide sufficient cooling/heating of the given enclosed space. Furthermore, medium sized residences, stores, and such other facilities are generally cooled/heated by small units operating in parallel. Operating multiple units together creates problems in control and cooperation of the units. To overcome such problems, two units are twinned and controlled together so that both units function identically providing more effective cooling/heating and avoiding large swings in room temperature.
Typically units are twinned/synchronized for improved airflow or to maintain adequate amount of air pressure. Twinning is used in applications where more heating or airflow capacity is needed than what one unit can deliver. Twinning is used to make two units operate in tandem, using a single duct system and a feedback system causing units to turn ON/OFF simultaneously.
To provide efficient cooling/heating, control systems are based on the characteristics of associated units as well as requirements of the enclosed space. Control systems typically communicate control information between twinned/synchronized units. In certain situations where units are located far away from each other, communicating control information between the twinned/synchronized units becomes more complex, especially if data is to be communicated on a single line. As units become even more sophisticated and perform more advanced functions, complexity of control systems and communication between the systems increase.
As used herein, the expression “unit” refers to and includes, but is not limited to, an HVAC unit, a furnace, an air-handler, a thermostat, a temperature control unit, a pressure control unit, an electric motor, a compressor, a valve, a regulator, a gearbox, a circulator, and the like. The expression “controller” used herein refers to and includes, but is not limited to, microcontrollers, microprocessors, Application Specific Integrated Circuits (ASIC), Digital Signal Processors (DSP), and the like. These definitions are in addition to those expressed in the art.